Tubular medical prosthesis

Abstract

A tubular prosthesis including a tubular wall portion of loosely interlocked pattern, e.g. of knitted loops, constructed to function within a body lumen. The loops are preferably formed of co-knitted strand materials. A first strand material is a metal strand that structurally defines the tubular shape of the prosthesis and maintains the shape when positioned in the lumen. A second strand material is a predetermined substance selected to provide desired characteristics to the wall of the prosthesis.

What is claimed is: 
     
       1. An implantable tubular prosthesis comprising: a tubular wall portion of loosely interlocked knitted loops defining open areas in said tubular wall, said wall being formed of at least two separate strands of different materials that are parallel co-knitted to form a unitary wall structure including a first strand that is a metal wire that structurally defines the tubular shape of said prosthesis and maintains said shape when positioned in said lumen and   a second strand, parallel co-knitted with said first strand, and comprising a predetermined material selected to provide desired characteristics to the wall of said prosthesis.   
     
     
       2. The prosthesis of claim 1 wherein said second strand is formed of a body fluid-dissolvable suture material. 
     
     
       3. An implantable vascular graft prosthesis for bridging an aneurysm in an arterial lumen of the body, comprising: a tubular wall portion of loosely interlocked knitted loops defining open areas in said tubular wall constructed to prevent excessive bleeding through the wall by inducing an initial clotting when the graft is placed in said lumen and to allow cells to migrate through said wall to endothelialize said graft,   said wall being formed of at least two separate strands of different materials that are parallel co-knitted to form a unitary wall structure including a first strand that is a metal wire that structurally defines the tubular shape of said prosthesis and maintains said shape when positioned in said lumen and   a second strand, parallel co-knitted with said first strand, comprising a predetermined non-metallic material selected to extend at least partially into space defined by the knit loops of the first strand to induce said initial clotting while maintaining sufficient open area so cells can migrate through said wall to endothelialize the graft.   
     
     
       4. The prosthesis of claim 1 or 3 including an anchoring end portion of knitted loops, knitted integrally with at least a portion of said co-knitted wall portion and formed of a strand material adapted to make contact with the wall of said body lumen to maintain the axial position of said prosthesis in said body lumen. 
     
     
       5. The prosthesis of claim 4 wherein said anchoring end portion is formed of contiguous loops of said first, metal strand material joined integrally with the said wall portion that includes said co-knit second strand. 
     
     
       6. The prosthesis of claim 1 or 3 wherein an anchoring end portion of said prosthesis is self-expanding, being formed of elastic metal strand capable of being reduced in radial size without plastic deformation and retaining self-restoring capability, whereby said end portion can be reduced to a relatively small size for introduction lengthwise into said lumen, and when freed can radially self-expand to tubular form to engage the wall of said lumen. 
     
     
       7. The prosthesis of claim 6 wherein said wall portion is expandable to desired size by means of an internal expanding force. 
     
     
       8. The prosthesis of claim 1 or 3 wherein said wall portion is expandable to a desired size by means of an internal expanding force. 
     
     
       9. The prosthesis of claim 8 wherein said first strand material of said wall portion is a plastically deformable metal, said wall portion being expandable to a desired size by application of an internal expanding force. 
     
     
       10. This prosthesis of claim 9 having an anchoring end portion formed of said plastically deformable metal and is knit integrally with said wall portion. 
     
     
       11. The prosthesis of claim 1 or 3 having an anchoring end portion formed of metal strand flared to a diameter greater than the wall portion. 
     
     
       12. The prosthesis of claim 1 or 3 including an anchoring portion at each of its axial ends. 
     
     
       13. The prosthesis of claim 1 or 3 wherein said first strand is selected from the group consisting of tantalum and nitinol. 
     
     
       14. The prosthesis of claim 13 wherein said second strand is selected from the group consisting of dacron, wool, nylon, polyethylene and teflon. 
     
     
       15. The prosthesis of claim 1 or 3 wherein the material of said second strand is textured to induce blood clotting. 
     
     
       16. The prosthesis of claim 15 wherein said prosthesis is sized for use as an aortic graft. 
     
     
       17. The prosthesis of claim 15 wherein said graft has a porosity of about 4000 ml/min or more at implantation. 
     
     
       18. The prosthesis of claim 1 or 3 wherein said wall portion includes a highly elastic strand and is self-expanding. 
     
     
       19. The prosthesis of claim 1 or 3 wherein said second strand is an absorbing member that includes a drug. 
     
     
       20. The prosthesis of claim 1 or 3 wherein said co-knit strands are in a parallel co-knit pattern. 
     
     
       21. An implantable vascular prosthesis for use in an arterial lumen of the body comprising: a tubular wall portion of loosely interlocked knitted loops defining open areas in said tubular wall, said wall being formed of at least two separate strands of different materials that are parallel co-knitted to form a unitary wall structure, including a first strand of said loops that is a metal wire that structurally defines the tubular shape of said prosthesis and maintains said shape when positioned in said lumen and   a second strand, parallel co-knitted with said first strand and comprising a textured textile strand selected to provide enhanced clot-inducing characteristics to the wall of said prosthesis.   
     
     
       22. The prosthesis of claim 21 wherein said wall portion is expandable to a desired size by means of an internal expanding force. 
     
     
       23. The prosthesis of claim 22 wherein said first strand material of said wall portion is a plastically deformable metal, said wall portion being expandable to a desired size by application of an internal expanding force. 
     
     
       24. The prosthesis of claim 23 having an anchoring end portion formed of said plastically deformable metal and knit integrally with said wall portion. 
     
     
       25. An implantable tubular graft prosthesis comprising: a tubular wall portion of a loosely interlocked regular pattern of strands defining open areas in said wall constructed to prevent excessive bleeding through the wall by inducing an initial clotting when the graft is placed in said lumen and to allow cells to migrate through said wall to endothelialize said graft,   said wall being formed of at least two separate strands of different materials that are integrated in parallel in said pattern to form a unitary wall structure, including a first strand that is a metal wire that structurally defines the tubular shape of said prosthesis and maintains said shape when positioned in said lumen, and   a second strand, in parallel extension and integrated with said first strand as part of said pattern forming said wall, said second strand formed of a material selected to extend at least partially into space defined by the first strand to induce said initial clotting while maintaining sufficient open area so said cells can migrate through said wall to endothelialize said graft.   
     
     
       26. The tubular prosthesis of claim 25 wherein said pattern is formed by co-weaving said strands. 
     
     
       27. The tubular prosthesis of claim 25 wherein said pattern is formed by co-crocheting said strands. 
     
     
       28. The tubular prosthesis of claim 26 or 27 wherein said pattern is formed of multiple parallel strands. 
     
     
       29. The prosthesis of any one of claims 1, 3 wherein said second strand material comprises a multi-filament textile which has been texturized to produce segments that extend radially outward from said strand.